Veneer and process for producing the same

ABSTRACT

A process for producing a veneer is disclosed wherein a layer made from a polyolefin, a copolymeric polyolefin or both is applied to a veneer sheet using heat and/or pressure. A veneer produced using this process is also disclosed.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The invention relates to a process for producing a veneer and toa product produced in this way.

[0003] 2. Description of the Related Art

[0004] In order to restrain as far as possible the use of high-valuetimbers, it is nowadays usual to cover the surfaces of a wide variety ofarticles, e.g. of furniture, with wood veneer.

[0005] The object of the invention is to provide a veneer which makesoperations easy and cost-effective, retains the aesthetic impression ofthe high-quality timber and can accept chemical and physical stresses.

BRIEF SUMMARY OF THE INVENTION

[0006] The novel process for producing a veneer of this type comprisesthe steps of

[0007] a) applying to a veneer sheet a layer made from the groupconsisting of a polyolefin, a copolymeric polyolefin and a mixture ofpolyolefin and copolymeric polyolefin and

[0008] b) bonding to one another the veneer sheet and the material ofthe layer.

[0009] A veneer sheet is therefore to be understood here as aconventional veneer made from timber, e.g. from a high-value timber. Theproduct produced according to the invention, i.e. the veneer in thesense of this application, is then the veneer sheet processed in themanner described above, i.e. a product in which the wood veneer sheethas been penetrated by the above-mentioned polyolefins or copolymericpolyolefins, etc.

[0010] This gives a veneer which has significantly better shapeabilitythan conventional veneer sheets. This opens up a broad range ofapplications for veneers and also allows dramatic simplification ofoperations with veneers compared with the prior art.

[0011] Preference is given to application by pressure in step (b) atpressures of from 5 to 20 bar. Temperatures preferred for theapplication by pressure are in the range from 150 to 200° C.

[0012] A particularly preferred embodiment of the invention providesthat ESI is used as the layer which, with pressure and/or heat,penetrates the wood veneer sheet. ESI is an ethylene-styreneinterpolymer supplied by Dow Chemical under this name. It is acopolymeric polyolefin. Its properties with respect to the presentinvention are in particular very good adhesive bonding performance (withpressure and temperature), good shapeability, good capability fordecoration by the “release” method and good coatability.

[0013] Further preferred embodiments of the invention are described inthe dependent claims.

[0014] A particularly preferred embodiment of the invention providesthat the layer to be applied by pressure to the wood veneer sheet has atleast two sublayers with different proportions of ethylene and styrene,where the sublayer initially facing the wood comprises more ethylenethan does the sublayer initially facing away from the wood.

[0015] A veneer produced according to the invention is preferablyfurther processed by being clamped, in the final shape (structure)desired, into an injection moulding machine and being back-moulded withplastic in a manner known per se. This gives a stable high-qualityproduct with a surface which is of high quality and which is inparticular aesthetically attractive. The surface has good coatabilityand capability for decoration.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The invention is described below by way of example, using thedrawing. This shows:

[0017]FIG. 1 is a diagram illustrating the novel process using a veneersheet and a layer lying thereupon;

[0018]FIG. 2 is a diagram of a preferred working example of thepolyolefin layer to be processed; and

[0019]FIG. 3 is a diagram of a veneer produced according to theinvention.

DETAILED DESCRIPTION OF THE INVENTION

[0020] A veneer sheet 10 is firstly prepared from timber.

[0021] A layer 12 is applied to the wood veneer sheet 10. The layer 12is composed, for example, of a polyolefin and/or of a copolymericpolyolefin or of a mixture comprising at least one of theseconstituents.

[0022] The material ESI is preferred for the layer 12, that is to say anethylene-styrene interpolymer (supplied as ESI by Dow Chemical). Theadvantageous properties of this material have been mentioned above.

[0023] Depending on the use intended, the thickness of the wood veneersheet 10 is, for example, in the range from 200 μm to 1 mm.

[0024] The thickness of the layer 12 applied, made from ESI for example,is preferably from 20 to 200 μm, depending on the thickness and thedesired properties of the veneer to be produced.

[0025] The layer 12 is then applied by pressure to the veneer sheet 10,whereupon the material of the layer 12 penetrates into the porous woodof the veneer sheet 10. The pressures used may be in the range from 5 to20 bar. The temperatures which prevail are preferably in the range from150 to 200° C.

[0026] This gives a veneer which is easy to shape and has goodmechanical, physical and chemical properties.

[0027]FIG. 2 shows a particular embodiment of the layer 12 for use witha wood veneer sheet 10 as in FIG. 1 (the wood veneer sheet 10 is notshown again in FIG. 2). The layer 12 as in FIG. 2 is composed of twosublayers 12 a and 12 b. ESI is the material intended for both layers.The lower sublayer 12 a of the layer 12 comprises more ethylene thandoes the upper sublayer 12 b. During further processing of the layer 12,the lower sublayer 12 a is undermost when applied to the wood veneersheet 10. When pressure and temperature are applied, as described above,the ethylene then penetrates more effectively into the porous woodmaterial of the veneer sheet 10. The higher styrene concentration in theupper sublayer 12 b gives the resultant veneer better surfaceproperties.

[0028] The two layers 12 a and 12 b may be extruded, for example, by acoextrusion process know per se.

[0029]FIG. 3 illustrates diagrammatically the veneer 10′ produced inthis way, i.e. the veneer sheet 10 with the polyolefins or copolymericpolyolefins, in particular ESI, or mixtures of these, which havepenetrated the veneer sheet. The layer 12 does not have to penetratecompletely homogeneously into the veneer sheet 10. It is perfectlyacceptable for there to be a concentration gradient in the final productin the direction of the arrow P in FIG. 3. This applies in particular ifthe layer 12 used has a number of sublayers and different componentswhich intentionally differ in their penetration into the wood material.

[0030] The invention has been described with reference to preferredembodiments which are merely illustrative of the present invention andnot restrictive thereof. Obvious modifications and alterations of thepresent invention may be made without departing from the spirit andscope of the present invention. The scope of the present invention isdefined by the appended claims and equivalents thereto.

We claim:
 1. A process for producing a veneer comprising the steps of: a) applying to a veneer sheet a layer made from the group consisting of a polyolefin, a copolymeric polyolefin and a mixture of polyolefin and copolymeric polyolefin and b) bonding to one another the veneer sheet and the material of the layer.
 2. The process according to claim 1 wherein bonding the veneer sheet to the material of the layer occurs with pressure.
 3. The process according to claim 2 wherein the pressure is between 5 to 20 bars.
 4. The process according to claim 1 wherein bonding the veneer sheet to the material of the layer occurs with temperature.
 5. The process according to claim 4 wherein the temperature is between 150-200 degrees centigrade.
 6. The process according to claim 1 wherein the layer comprises ethylene-styrene interpolymer (ESI).
 7. The process according to claim 6 wherein the layer is comprised of at least two sublayers and each sublayer has a different proportion of ethylene and styrene.
 8. The process according to claim 7 wherein the layer is comprised of at least a first sublayer and a second sublayer wherein the first sublayer contacts the veneer sheet and has more ethylene than does the second sublayer.
 9. The process according to claim 1 wherein the thickness of the layer is between 20 to 200 micrometers.
 10. The process according to claim 1 wherein the thickness of the veneer is between 200 micrometers to 1 millimeter.
 11. A veneer composite comprised of: a) a veneer sheet made of wood, and b) a layer made from the group consisting of a polyolefin, a copolymeric polyolefin or a mixture of the two.
 12. The veneer composite according to claim 11 wherein the layer is comprised of ethylene-styrene interpolymer (ESI). 